Zone 3 · Leafy Greens Growing Guide

When to Plant Collard Greens
in Zone 3

The most heat-tolerant and cold-hardy of all the brassica greens. Harvest outer leaves all season. Flavour improves dramatically after frost. A Southern US staple.

Plant outdoors
May 15 – Aug 1
Start indoors
Apr 10 – May 1
Last Frost
~May 15
Days to harvest
60–80 days
Difficulty
Easy
Start indoors — Zone 3
Harvest window: Jul – Nov

Planting Calendar

In Zone 3, Collard Greens should be planted outdoors May 15 – Aug 1, after the average last frost date of approximately May 15. Start seeds indoors around Apr 10 – May 1 for a head start.

Spring planting plus midsummer direct sow for fall crop. Frost sweetens flavour considerably.

Care Guide

Sunlight
Full sun to partial shade · 4–8 hrs/day
Watering
Regular
Spacing
18–24 inches
Soil
Fertile, well-draining
Days to maturity
60–80 days
Soil pH
6.0–7.5
plant tip · Zone 3

Spring planting plus midsummer direct sow for fall crop. Frost sweetens flavour considerably.

Feeding Schedule

How often
monthly
Feed type
high nitrogen
Key timing
throughout growing season

Heavy feeder. Nitrogen produces large, tender leaves. Feed monthly throughout the season.

Succession Planting

Sow every 4 weeks

Sow every 4 weeks from spring through midsummer. More heat-tolerant than most brassicas, making succession easier in warmer zones.

Companion Planting for Collard Greens

What you plant next to collard greens makes a real difference — some plants actively help, others compete or attract pests.

Grows well with
  • Beans
  • Onions
  • Beets
  • Celery
Keep away from
  • Tomatoes
  • Strawberries
  • Fennel

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Common questions

In Zone 3, start collard greens seeds indoors around Apr 10 – May 1, then transplant outdoors May 15 – Aug 1 after your last frost around May 15. Spring planting plus midsummer direct sow for fall crop. Frost sweetens flavour considerably.
Zone 3 has an average last spring frost of approximately May 15 and a first fall frost around Sep 15. These dates vary by specific location — use your ZIP code in the plant app for precision based on the nearest NOAA weather station.
Good companion crops for collard greens include Beans, Onions, Beets, Celery. Avoid planting near Tomatoes, Strawberries, Fennel, which can compete for nutrients or attract pests.
Collard Greens typically takes 60–80 days from transplant or direct sow to harvest in Zone 3. Expected harvest window: Jul – Nov.

Free app · iOS February 2028

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Collard Greens in other zones
Crop Guides